Monitoring of gene expression in tacrolimus-treated de novo renal allograft recipients facilitates individualized immunosuppression: Results of the IMAGEN study

Pharmacodynamic monitoring by residual gene expression of the nuclear factor of activated T cell-regulated genes in lung transplant recipients and its correlation with tacrolimus blood levels

Introduction

Trough blood levels (C0) of tacrolimus are used to adjust drug dosage, but they do not consistently correlate with clinical outcomes. Measurement of residual gene expression of nuclear factor of activated T cell (NFAT)-regulated genes (NFAT-RGE) has been proposed as a pharmacodynamic biomarker to assess the degree of immunosuppression in certain solid organ transplantations, but little is known regarding lung transplant recipients (LTR). Our primary objective is to correlate tacrolimus blood levels with NFAT-RGE.

Methods

NFAT-RGE and tacrolimus C0 and peak (C1.5) levels were determined in 42 patients at three, six and 12 months post-transplantation.

Results

Tacrolimus C0 did not exhibit a correlation with NFAT-RGE, whereas C1.5 did. Besides, over 20% of measurements indicated high levels of immunosuppression based on the below 30% NFAT-RGE threshold observed in many studies. Among those measurements within the therapeutic range, 19% had an NFAT-RGE<30%.

Conclusion

Consequently, a subset of patients within the tacrolimus therapeutic range may be more susceptible to infection or cancer, potentially benefiting from NFAT-RGE and tacrolimus peak level monitoring to tailor their dosage. Further quantitative risk assessment studies are needed to elucidate the relationship between NFAT-RGE and the risk of infection, cancer, or rejection.

Biomarkers for Kidney-Transplant Rejection: A Short Review Study

Kidney transplantation is the preferred treatment for end-stage renal failure, but the limited availability of donors and the risk of immune rejection pose significant challenges. Early detection of acute renal rejection is a critical step to increasing the lifespan of the transplanted kidney. Investigating the clinical, genetic, and histopathological markers correlated to acute renal rejection, as well as finding noninvasive markers for early detection, is urgently needed. It is also crucial to identify which markers are associated with different types of acute renal rejection to manage treatment effectively. This short review summarizes recent studies that investigated various markers, including genomics, histopathology, and clinical markers, to differentiate between different types of acute kidney rejection. Our review identifies the markers that can aid in the early detection of acute renal rejection, potentially leading to better treatment and prognosis for renal-transplant patients.

Pharmacodynamic Monitoring of Ciclosporin and Tacrolimus: Insights From Nuclear Factor of Activated T-Cell-Regulated Gene Expression in Healthy Volunteers

BACKGROUND

Although therapeutic drug monitoring of calcineurin inhibitor (CNI) concentrations is performed routinely in clinical practice, an identical concentration may lead to different effects in different patients. Although the quantification of nuclear factor of activated T-cell-regulated gene expression (NFAT-RGE) is a promising method for measuring individual CNI effects, CNI pharmacodynamics are as of yet incompletely understood.

METHODS

CNI concentrations and NFAT-RGEs were quantified in 24 healthy volunteers receiving either ciclosporin or tacrolimus in 2 clinical trials. NFAT-RGE was measured using quantitative reverse transcription polymerase chain reaction tests of whole-blood samples. Pharmacokinetics and pharmacodynamics were analyzed using compartmental modeling and simulation. In addition, NFAT-RGE data from renal transplant patients were analyzed.

RESULTS

The average NFAT-RGE during a dose interval was reduced to approximately 50% with ciclosporin, considering circadian changes. The different effect-time course with ciclosporin and tacrolimus could be explained by differences in potency (IC 50 204 ± 41 versus 15.1 ± 3.2 mcg/L, P < 0.001) and pharmacokinetics. Residual NFAT-RGE at the time of maximum concentration (RGE tmax ) of 15% when using ciclosporin and of 30% when using tacrolimus was associated with similar average NFAT-RGEs during a dose interval. Renal transplant patients had similar but slightly stronger effects compared with healthy volunteers.

CONCLUSIONS

Ciclosporin and tacrolimus led to similar average suppression of NFAT-RGE in a dose interval, despite considerably different RGE tmax . Pharmacodynamic monitoring of average NFAT-RGE should be considered. When using NFAT-RGE at specific time points, the different effect-time courses and circadian changes of NFAT-RGEs should be considered.

Monitoring of Ex Vivo Cyclosporin a Activity in Healthy Volunteers Using T Cell Function Assays in Relation to Whole Blood and Cellular Pharmacokinetics

Therapeutic drug monitoring (TDM) of calcineurin inhibitors (i.e., tacrolimus and cyclosporin A) is standard of care after solid organ transplantation. Although the incidence of acute rejection has strongly decreased, there are still many patients who experience severe side effects or rejection after long-term treatment. In this healthy volunteer study we therefore aimed to identify biomarkers to move from a pharmacokinetic-based towards a pharmacodynamic-based monitoring approach for calcineurin inhibitor treatment. Healthy volunteers received a single dose of cyclosporine A (CsA) or placebo, after which whole blood samples were stimulated to measure ex vivo T cell functionality, including proliferation, cytokine production, and activation marker expression. The highest whole blood concentration of CsA was found at 2 h post-dose, which resulted in a strong inhibition of interferon gamma (IFNy) and interleukin-2 (IL-2) production and expression of CD154 and CD71 on T cells. Moreover, the in vitro effect of CsA was studied by incubation of pre-dose whole blood samples with a concentration range of CsA. The average in vitro and ex vivo CsA activity overlapped, making the in vitro dose–effect relationship an interesting method for prediction of post-dose drug effect. The clinical relevance of the results is to be explored in transplantation patients on calcineurin inhibitor treatment.

TLR10 genotypes affect long-term graft function in tacrolimus-treated solid organ transplant recipients

The present study was conducted to investigate the relationship between single nucleotide polymorphisms (SNPs) in TLR10 and the clinical outcomes of renal transplant patients who took tacrolimus (TAC) as an immunosuppressant, and further confirmed the results in liver transplant patients. A total of 172 renal transplant patients and 145 pairs of liver transplant recipients and donors were included. Nineteen SNPs of TLR10 gene were detected by matrix-assisted laser desorption ionization-time-of-flight-mass spectrometry (MALDI-TOF-MS). The associations of recipient SNPs with TAC-related clinical outcomes were explored in renal transplant recipients. The relationship between recipient and donor SNPs and the clinical outcomes of liver transplant patients were investigated to confirm the results. Three SNPs (rs28393318, rs11466655 and rs11096957) in renal transplant recipients were found to influence the graft function after transplantation (P = 0.00003, 0.001 and 0.000003, respectively). The recipient rs11096957 was also found to affect the TBil, and DBil levels in liver transplant recipients (P = 0.001 and 0.002). In this study, we identified significant association signals from TLR10 polymorphisms with clinical outcomes in TAC-treated transplant patients in a Chinese Han-based sample. We provide some evidence for the effect between rs11096957 in TLR10 gene on the graft functions in both renal and liver transplantation.